One more thing that rings —

Plugin-free Skype on the Web a step closer with Edge support

But interoperability is still a bit of a mess.

Since November 2014, Microsoft has been working to build a plugin-free version of Skype that will run in the browser. That work took a step forward today, with support for no-plugin voice and video calling in Microsoft's Edge browser.

However, the support is quite limited. It requires the latest version of Edge, as shipped in Windows 10 version 1511 (build 10586). Both one-to-one and group chats are available in Edge-to-Edge calls without plugins, and one-to-one calls to the very latest version of Skype for Windows and OS X are also plugin-free. But any other combination—different browsers, older versions of Skype, or group calls to the desktop Skype clients—will still need a plugin.

Skype in the browser remains an awkward combination. There are two related specs within the browser for real-time communication (RTC), the earlier WebRTC, and the derived but different Object RTC. Edge has preliminary support for ORTC, and a JavaScript library to provide WebRTC compatibility for audio, but not video, has been developed. After long pushing back against WebRTC, Microsoft has said that it will build partial support for the specification into the browser to enable video support on top of audio in basic one-to-one situations.

Aside from these Web spec issues is the matter of codec support. Edge's ORTC supports H.264UC, a subset of H.264 SVC (Scalable Video Coding), which is itself an extension to the H.264 video codec that provides the ability to change the bitrate and resolution of a stream on the fly. Edge doesn't support vanilla H.264, though Microsoft is working on adding it to both ORTC and WebRTC. Firefox supports H.264 in WebRTC, but Chrome currently only includes VP8 support. Without a compatible codec, two browsers can't communicate directly. Chrome should be gaining H.264 support soon—it's currently available as an off-by-default feature of the early-access Chrome Canary development branch—and Microsoft is evaluating adding VP8 support to both ORTC and its WebRTC implementation.

One day plugin-free Skyping from the browser will be easy and compatible. But right now it's all a bit of a mess.